Evolution of Man

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The big question• One question that has preoccupied humans is

“Where did we come from?”• A seemingly simple question…• But it is responsible for a number of myths, stories,

beliefs .. With everyone trying to answer the mystery of creation

• Let us explore this question together and hopefully find an answer

The most common answer

• The most common scientific answer for this question is “We came from Monkeys”!

• Well this answer is not completely true!• Through this video we will travel Millions of years

back in time to unravel how modern humans evolved from many other creatures of the past.

• We will go through eras that spanned tens of millions of years and meet creatures with unpronounceable names but from whom we inherited some characteristics which make us today’s modern humans!

Tools for this discovery• How do we re-construct a story that is millions of years

ago? How do we know these creatures actually existed and how do we know their characteristics?

• These are all very valid questions• The answer lies in fossils of these creatures!• Fossils are the remains of plants and animal material like

seeds, teeth, bones, skulls, shells etc. Some of the fossils that survive millions of years actually become very hard like rocks

• Fossils have been discovered in many parts of the world today and with each fossil found, we understand a little bit more about the past!

• As we go through this evolution story we should realize that as we speak new fossils are being discovered, and new theories are being proposed. So a few years from now there might be more information on our ancestors. Just like humans, the science of humans is also constantly evolving

Before the Apes• OK Let’s get back to our story of humans and

apes and monkeys!• In any zoo the apes – gorillas, chimpanzees and

orangutans attract the most attention. Ever wonder why?

• They not only amuse us by their antics and expressions and gestures but we are also amazed by their intelligence. Maybe they remind us a bit about ourselves

• So very often it is misunderstood that today’s humans must’ve descended from these apes as we are so much like them in some respects.

• But to understand where we came from we have to look beyond the apes

Our cousins .. The apes• In reality humans are linked to apes as cousins

and we descended from common ancestors as this diagram shows

Common Ancestor

Orangutan Gorilla Chimpanzee Bonobo Human

The story beyond apes• To truly tell the story we have to look beyond apes and

even beyond monkeys and find out where primates came from

• Primate is the term used for the group to which monkeys, apes and humans belong

• This story takes us to 70 Million years ago and this age was called Paleocene

• As we go through the story look for those characteristics which humans might have inherited from each of these ancestors and those that they did not. They will be highlighted with

Sidebar – Can you tell the difference between monkeys and apes?• Monkeys have tails while apes do not• Most monkeys cannot swing from one branch to another – they can run along the tops

of branches – unlike apes• Apes are much more like human beings and are more intelligent than monkeys

Prosimians• Paleocene age was when the world was warm enough for creatures to

survive.The earth was covered with tropical forests from the equator to Europe and South Africa.

• Small rat like creatures with tails and leaping about in trees lived at that time.

• Are you wondering why do we care about such rodents?• Well, these creatures used their eyes to hunt and were able to hold

things in their claws. Also their brains started to develop and they could distinguish colors… and these are all things that humans do!

• These were the early primates and they are called prosimians.• They were on their way to becoming monkeys over 40 million years!

No one said evolution was fast! • Some of the surviving prosimians are lemurs, sifakas and aye-ayes

Oligopithecus & Propliopithecus• So let’s fast forward to the Oligocene age. Fossils

discovered in Egypt gave scientists some clues about a primate called Oligopithecus!

• What was so important about the Oligopithecus was the fact that it had 32 teeth!! And you know who else has 32 teeth ? Some monkeys (called old world monkeys), apes and of course humans!

• One more species that lived around the same time was the Propliopithecus. They left us a legacy of 5 cusped teeth – which is again seen in apes and humans but not so much in monkeys!

• So scientists concluded that the Propliopithecus was gradually moving towards becoming apes

• We will now see how creatures progressed with time and how man evolved

Pliopithecus

• The pliopithecus lived in the Miocene age about 20 Million years ago

• The pliopithecus had a flat face, 5 cusped teeth, free-swinging arms and semi-upright posture

• It was one of the ancestors for apes and is now widely considered as the ancestor to the gibbon which is the least human-like among all apes

Ancestor of

Pliopithecus Gibbons

Proconsul

• Along with the Pliopithecus lived the proconsul• They are believed to be the ancestors of today’s chimpanzees and even gorillas

but they were not the ancestors for humans.• How do we know that? The answer lies in the jaw!• When you stand in front of the mirror with your mouth wide open – what do you

observe about the roof of your mouth (also called palate)? Yes it is arched isn’t it? Well the palate of an ape is not arched. It is flat and so was that of the Proconsul! That’s one of the reasons why they are ancestors of apes and not of humans

Ancestor of

ProconsulChimpanzee

Ramapithecus• The ramapithecus which lived about 15

Millions years ago was once considered to be the earliest man-like primate discovered so far.

• How did scientists conclude that?• Once again fossils of the teeth and jaw

gave us the clues!• The fossils revealed that the

Ramapithecus had curved jaws (narrow in front, broader behind) just like today’s modern humans

• Also their teeth were all about the same size… just like humans again! (In apes the front teeth are much longer than the rest)

• But in 1976-77 a complete jaw was discovered and it now revealed that the jaw was closer to apes than humans. So now Ramapithecus is considered to be the ancestor of apes and not of humans

Australopithecus• 9 Million years after the Ramapithecus, lived the

Australopithecus. During these 9Million years our ancestors made numerous advances including the ability to stand erect on 2 legs.

• Fossils revealed a horizontal spinal column and a number of other modifications to the spinal cord which must’ve undergone these changes for standing erect on 2 legs

• Also teeth discovered offered one more clue! The teeth were all touching each other just like in humans!

• But why did these creatures get down from trees and start to walk? There are a number of theories– Searching for food on the ground– Ability to use tools like stones and sticks which could

help them hunt small creatures

• Based on these theories it is believed that the Australopithecus must’ve been a tool user and two legged creature

Advanced Australopithecus

• The Australopithecus started as a small creature but evolved at a very fast rate. In about a million years he grew larger and more man-like. In another million years he became a man! (yes one million years is very fast for evolution!)

• A number of tools that were supposedly used by the Australopithecus have been discovered by scientists. Tools like sticks and stones must’ve been used to catch and kill small animals and to dig into the ground

• The advanced Australopithecus was as the name indicates more “advanced” than the Australopithecus in terms of brain activity. The advanced type was larger, smarter and stronger and are believed to have evolved into humans

More about the Australopithecus• 7 species of Australopithecus have now been identified• Of these 7, Australopithecus Afarensis which dates back to 3.75M

years ago is widely regarded as the ancestor to all the other species of Australopithecus

• The Afarensis fossils reveal they were probably between 1 to 1.6m tall and weighed about 20 to 50 kg

• Fossils of another Australopithecus species called A.Africanus suggest that they were closer to humans than Afarensis.

• There are a number of theories about the connections between the various species of Australopithecus and their connection to Homo Habilis (the first of the humans)

• Some believe that Australopithecus evolved into 2 main groups one of which became extinct and one eventually evolved into Homo Habilis – some believe that A.Africanus was the species that evolved into Homo Habilis, while others disagree

• In any case, the main contribution of Australopithecus was the bi-pedal trait

• The story from now on is about early humans!

Homo Habilis and Homo Erectus• The first member of the human family was the Homo Habilis. They

showed a significant expansion of the brain (750cc) which has become a trait in humans. Over time the Habilis evolved into a larger, robust, larger brained species called the Homo Erectus

• The Homo Erectus were seen on the earth about 500,000 years ago. They are the first men. They had modern limbs but primitive brain (with capacity about 900cc to 1050cc). One interesting aspect was that they seemed to know how to use fire! They must’ve seen natural fires and must’ve felt the warmth of the fire. The other theory is that they must’ve discovered fire by accident when rubbing flint tools

• The Homo Erectus were originally vegetarians and later became meat eaters. In order for them to digest the meat they must’ve known how to cook with fire.

• Physically the Homo Erectus was much more advanced than the Australopithecus – legs were long and straight, brain was larger than Australopithecus but smaller than that of a modern man and they also mastered some sort of speech

• The Homo Erectus were better tool makers than the Australopithecus and might have invented a crude hand-axe

• What is not clear is how the HomoErectus spread from Africa to other continents. What is known is that they were superb walkers. Over centuries their bands must’ve spread inch by inch across the continents. The humans finally arrived!

Neanderthal Man• The Neanderthal man arrived on the scene about

100,000 years ago.• They represented stone-age humans and they

come to our mind when we think of our ancient relatives

• They are not the dim-witted brutes that they were once believed to be

• In fact we now learn that they were excellent hunters and tool makers. They had a language of their own and started showing some signs of culture of their own

• They seemed to have thought about life and death and also about religion– They buried their dead with the body positioned as though

they were in sleep– They even aligned the bodies of the dead in east-west

direction

Cro Magnon – Arrival of Modern Man• As we saw in the last two slides traces of

modern man go back to several hundred thousand years ago but modern man in his current form did not emerge until 35,000 years ago

• Most fossil evidences from 35000 BC are from Europe so we know a lot about these men but not as much about the humans in Africa (although we know that Africa was full of people at that time), Australia, N.America

• The name of the humans that lived in Europe at that time was Cro-Magnon

• It was during this time that differentiation into various human races started to happen

More about the Cro-Magnon Man• The cro-magnons had a culture of their own which flourished as

their life improved• They still lived in caves but in large groups on a permanent basis• They started to stitch skins into clothes• With their large brain they began developing new tools and even

found time for art (70 sites of Cro-Magnon cave art was found in France alone)

• The cro-magnons were also very good at sculpting and engraving• There was also spiritual advancement, belief in magic (depicted in

their art), respect for the dead (graves were discovered).• Although we do know a lot about cro-magnons there are still a

number of unknowns. But it is now accepted that they were only one cultural step away from today’s modern humans

Modern Man

• Between the contemporary humans and the cro-magnons there is 10,000 years. But modern man today is not very different physically from the Cro-Magnons

• What has set modern man apart is culture– Learning how to grow food– Domesticate animals– Give up nomadic life and find permanent

settlements and civilizations

Conclusion

• So that was the story of how humans evolved.• This journey took us through 50 to 70 Million years

and we met with so many creatures which are living today only as fossils

• But humans are constantly evolving and we are constantly learning from our past

• Humans have been able to adapt to changing conditions very well and have grown to become the most dominant species on the face of the earth.

• There are still a number of unanswered questions about humans. Maybe our past will hold some of the answers and we hope that today’s discussion answered at least some of those questions!